One of the recent developments in microelectronics packaging technology is through-silicon-via (TSV) interposers that allow more dense packaging of device chips by allowing 3-dimensional chip stacking. Because the TSV interposers are very thin, however, handling of the TSV interposers during the chip assembly process is challenging. Often, TSV Interposers are made of silicon waters having a thickness of 90 μm.
Referring to FIG. 10, a TSV interposer wafer 10 can be made from silicon wafer with typically copper-based through vias 12 extending through the thickness of the silicon wafer 10. On one side of the silicon wafer 10, the TSVs terminate forming pads for receiving flip-chip bonding chips. On the opposite side of the silicon wafer, the TSVs are electrically connected to metalized pads 14 by appropriate thin film wiring and solder bumps 16 are formed on the metalized pads for next level interconnection.
TSV interposers are generally mounted on a glass carrier 20 on the solder bump side using a UV tape 30 for handling purposes. The glass carrier 20 provides rigidity to the otherwise very thin (about 90 μm-150 μm thick) fragile TSV interposers and allow safer handling of the TSV interposer. While the TSV interposer is attached to the glass carrier 20, the back-side 10B (side opposite from the glass carrier) is ground and chemically etched to expose copper posts for subsequent flip-chip bonding.
After the grinding and etching processes, the glass carrier 20 is removed by irradiating the UV tape through the glass carrier with UV light so that semiconductor chips can be flip-chip bonded to the back-side 10B of the TSV interposer. Generally, the TSV interposers are fabricated as an array of TSV interposers in a wafer form and a semiconductor chip configured for flip chip bonding is placed on each TSV interposer in the array. After the semiconductor chips are placed on the TSV interposers, the TSV interposer wafer goes through a flip-chip bonding reflow process to bond the semiconductor chips to the TSV interposers. After the glass carrier 20 is removed, however, because the TSV interposer is fragile, the subsequent flip-chip bonding process becomes difficult and many TSV interposers can be lost due to breakage.